• Toxicological Research
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• v.35 no.3
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• pp.249-255
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• 2019

Cadmium is a strong toxic heavy metal which presents in paints and liquid wastes and causes oxidative stress in fish. On the other hand, lead is widely used for different purposes, e.g. lead pipes, it targets vital organs such as liver and kidney causing biochemical alterations. The present study evaluates the effects of 60 days exposure to Cd and Pb either single or combined together in African catfish. Sixty-four fishes were divided into 3 groups and exposed to $CdCl_2$ (7.02 mg/L) or $PbCl_2$ (69.3 mg/L) or a combination of them along with control group. Activities of acid phosphatase (ACP), lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) were estimated. Moreover, gill, liver and kidney were assayed for activities of superoxide dismutase (SOD), catalase (CAT) and levels of glutathione (GSH) and malondialdehyde (MDA). Individual exposure showed that both Cd and Pb significantly decreased LDH activity and SOD activity in the kidney. Pb significantly increased G-6-PDH activity and decreased GSH level in the gill. CAT activity in liver and kidney elevated significantly on Cd exposure while lead caused a significant depletion in the liver and significant elevation in the kidney. Both Cd and Pb significantly increased MDA levels in liver and kidney while Pb increased its level in gills. The combined exposure resulted in normalization of LDH, G-6-PDH activity, and CAT activity in liver and kidney as well as GSH level in both tissues and MDA in gill and kidney. The combination increased SOD activity and MDA level in liver and decreased SOD activity in kidney and GSH level in gills. In conclusion, the antioxidant system of African catfish was adversely affected by prolonged exposure to Cd and Pb. The combined exposure caused less damage than individual exposure and returned most parameters to those of controls.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.541-548
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• 2022

Biofloc technology (BFT) systems provides an additional protein source for fish by converting waste in microbial flocs. Therefore, we aimed to determine the difference in the protein levels of the diet of Far Eastern catfish Silurus asotus reared in BFT and FW systems. We applied a two-way (six protein levels × two aquaculture systems) ANOVA design. We formulated six experimental diets to contain different protein levels (CPs)- 20%, 25%, 30%, 35%, 40% and 45%-referred to as the CP20, CP25, CP30, CP35, CP40 and CP45 diets, respectively. We randomly distributed 900 fish into 36 (18 each for BFT and FW), 300 L tanks (25 fish/tank) with three replications of each diet for 4 weeks. The weight gain (WG) and specific growth rate (SGR) considerably improved as the dietary protein level increased in the formulated diets. The BFT fish showed higher growth performance with any experimental diet than the FW fish. The growth performance of the fish fed the BFT-CP35 diet was higher than that of the fish fed the FW-CP45 diet. In conclusion, the cultivation of Far Eastern catfish (S. asotus) in BFTs can be carried out under reduced dietary protein levels.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.545-553
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• 2019

This study was conducted to determine whether the water in which nitrate accumulated during long-term fish culture in an aquaponics system without water exchange could be removed and reused as catfish-culturing water. The catfish (Silurus asotus) were cultured in the urban aquaculture system using BFT (Biofloc Technology) aquaculture and an aquaponics system (two rearing tanks, 3 tons each) without exchanging the rearing water. After 151 days (from March to August) of rearing, 2.8 g of fry had grown to an average weight of 171.3 g (total weight, 56.53 kg) and 235.5 g (total weight 71.1 kg), respectively. The overall survival rate was 65% in the urban aquaculture system. However, the survival rate was 77.7% before separation into the two tanks. The survival rates after the separation were 92.9% and 78.0%. In the early biofloc watermaking process, there was a high mortality rate. After water stabilization, the mortality rate decreased and some mortality occurred during the period when the total amount of suspended solids (TSS) increased. The results of monthly blood analysis of the catfish showed that the AST concentration was significantly higher in April. Blood ALT levels and triglycerides showed no difference in the rearing period and the glucose, cholesterol, and total protein levels were significantly higher in July. There was no difference in the other periods. The plants produced by the aquaponics system using catfish-rearing water were lettuce, basil, chard, and red chicory. These showed smooth growth and a total of 148.85 kg of plants were harvested in five months. It was possible to remove nitric acid from the aquaponics system and reuse it as catfish-rearing water. Maintaining proper plant quantity according to the capacity of the catfish showed that the combination of agricultural and aquatic products was possible.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.598-602
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• 2008

Concentrated catfish Silurus asotus bile (SAB) containing high amounts of ursodeoxycholic acid (UDCA) and taurocholic acid may have immunosuppressive properties. To investigate the putative immunosuppressive properties of SAB, the anti-proliferation and suppression of early T cell activation markers, and the inhibition of cytokines induced by T cells in response to anti-CD3 mAb activation in mouse splenocytes were examined. The suppression of these activation repertoires are the main properties of calcineurin inhibitors. It was found that SAB effectively suppressed the activation of T cells, and cytokines from T cell activation, at levels similar to cyclosporine A, a calcineurin inhibitor. Although the mechanism in which suppression occurs is not clear, we speculate that SAB from Silurus asotus, which has been known to switch their intake habits to zoophagy during an early adult stage, may explain the suppressive effect of SAB as a result of high amounts of functional UDCA in bile. Our results suggest that the treatment or intake of SAB, either in therapy or as a food supplement, may act as an adjuvant therapy for the prevention of transplant rejection, although further investigation is required before this treatment can be applied clinically.

• Korean Journal of Animal Reproduction
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• v.19 no.2
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• pp.105-117
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• 1995

This study was carried out to investigate the histomorphological changes and the electrophoretic patterns of egg components, obtained from 100 of 1-year-old female catfish(Silurus asotus). Especially, the light microscopic and ultrastructural changes of ooplasm and follicular membranes of oocytes, were observed by light and transmission electron microscope. All data were collected from October in 1992 to May in 1993. The size of the nucleoli and number of the yolk granules increased as the oocyte grew. Yolk granules were deposited in the oocyte as fluid. Due to the presence of large early and late maturing oocytes, their ovaries were large, transparent, granular, and greenish in color. As the percentages of fish in LMO and RO stage increased from March to April, mean of GSI values(19.95%) increased. Follicle cells such as granulosa cell and thecal cell change a squamous into cuboid shape in LPO and EMO stage. Processes, microvilli, from the granulosa cells and from the oocyte grow and make contact with each other in the pore canals of the zona radiata during vitellogenesis, but are withdrawn as the zona radiate becomes more compact and devoid of pore canals during oocyte maturation. The electrophoretic pattern of major band in mature stage was much thicker(21k, 24k, 32k, 45k, 67∼110k, 170k dalton) than that in previtellogenic phase.

• Journal of Aquaculture
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• v.6 no.1
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• pp.47-53
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• 1993

Feeding trials were conducted for a test of the optimum dietary protein levels for the fingerling Korean catfish, Parasilurus asotus. The growth response was examined in terms of weight gain, feed coefficient. protein efficiency ratio and net protein utilization for 8 weeks at $23\~27^{\circ}C$. Within a range of 25 to 55\%$ crude protein levels in the diet, the body weight increased while the dietary protein level increased. Accumulation of protein in the body reached the maximum when the crude protein level in the diet was at $45\%$. These results indicate that the optimum dietary protein level of fingerling Korean catfish was about $45\%$ when anchovy meal was used as the protein source.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.380-384
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• 2004

The toxic impact of parathion on bagrid catfish (Pseudobagrus fulvidraco) juvenile was examined 96 hr $LC_{50}$ value of parathion estimated as 1 90 mg/L. Chronically, bagrid catfish were exposed for 30 days to concentrations of parathion, i.e. 63, 95, 190 and $380\;{\mu}g/L$, representing 3.3, 5.0, 10.0 and $20.0{\%}$ of the 96 hr $LC_{50}$. Survival rate was significantly affected by the concentration over $63\;{\mu}g/L$ after 10 days. Growth rate, specific growth rate (SGR) and feed efficiency were reduced in time as concentration dependent manner. Growth rates of the exposed groups were significantly reduced as $28.06-60.63{\%}$ to the control fish, SGR was decresed as $1.50-4.72{\%}$ and feed efficiency was declined as $6.10-11.90{\%}$. It can be concluded that if p. lulvidraco is chronically exposed to parathion over $63\;{\mu}g/L$ concentration, the physiological damages might affect growth factors of the fish.

• Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.109-114
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• 2004

To evaluate the impact of parathion on aquatic organisms, a freshwater bagrid catfish (Pseudobagrus fulvidraco) was exposed to sublethal concentrations $(63,\;95,\;190\;and\;380\;{\mu}g/L)$ of parathion, organophosphorus pesticide for 30 days. Glucose level in the serum of the bagrid catfish was significantly increased than that of control groups in the $190\;{\mu}g/L$ concentration at 30 days and in the $380\;{\mu}g/L$ concentration after 10 days. Bilirubin level was significantly increased in the $190\;{\mu}g/L$ concentration at the end of the experiment. After 10 days, a significant differences of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) activity increased in the ${\geq}190\;{\mu}g/L$ and $380\;{\mu}g/L$ groups. Though cholesterol concentration was stable, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in serum were significantly reduced in the $190\;{\mu}g/L$ at 10 days and in the $380\;{\mu}g/L$ concentration at the end of the experiment. In conclusion, if P. fulvidraco was chronically exposed to ${\geq}190\;{\mu}g/L$ concentration of parathion, the hematological changes may be induced due to the stress response.

• Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.359-365
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• 2015

We investigated the effects of dietary lipid sources on growth and fatty acid composition of juvenile Chinese longsnout catfish. Triplicate groups of fish (initial average weight, 3.8 g) were fed four diets containing either fish oil (FO), soybean oil (SO), linseed oil (LO) and lauric acid (LA) for 10 weeks. There were no differences among the groups in body weight, feed intake, feed efficiency, protein efficiency ratio, and body proximate composition of fish fed the diets containing different lipid sources (P > 0.05) during the study. However, fatty acids compositions of the whole body were influenced by dietary lipid source. Fish fed the SO diet had high concentration of linoleic acid, whereas those of fish fed the LO diet were rich in linolenic acid and arachidonic acid. Fish fed the FO diet had significantly (P < 0.05) higher levels of monounsaturated fatty acids such as 18:1n-9 and 20:1n-9 than those of fish fed the SO and LO diets. Eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) composition of body were not influenced by dietary lipid source. The results suggest that each of FO, SO, LO or LA can be used as a lipid source in the diets of Chinese longsnout catfish without any negative effects on growth and feed utilization and these data demonstrate the potential impact which dietary fat composition can change the body fatty acid profile.

• Journal of the Korean Applied Science and Technology
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• v.25 no.4
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• pp.418-428
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• 2008

Transesterification of fat of Tra catfish with methanol in the presence of the KOH catalyst yields fatty acid methyl esters (FAME) and glycerol (GL). The effects of the reaction temperature and reaction time on rate constants and kinetic order were investigated. Three regions were observed. In the initial stage, the immiscibility of the Tra fat and methanol limited the reaction rate, hence this region was controlled by the mass transfer. Subsequent to this region, produced FAME like a co-solvent made the reaction mixture homogeneous, therefore the conversion rate increased rapidly so it was controlled by the kinetic parameters of the reaction until the equilibrium was approached in the final slow region. A second-order kinetic mechanism was proposed involving second regions for the forward reaction. The rate determining step for the overall KOH catalyzed-methanolysis of Tra fat was the conversion of triglycerides (TG) to diglycerides (DG). This rate constant was increased from 0.003 to $0.019min^{-1}$ when the reaction temperature was increased from 35 to $60^{\circ}C$. Its calculated activation energy was 14.379 ($kcal.mol^{-1}$).